1. Technical Field
This is related to RF reflector devices, and more particularly, to satellite reflectors.
2. Related Technologies
Fleet Satellite Communications System satellites, which were launched in the years between 1979 and 1980, have provided UHF communications to the U.S. Navy. The UHF Follow-on System (UFO) constellation of satellites replaced the FLTSATCOM satellites, providing UHF capability to the US Navy, as discussed in D. H. Martin, A History of U.S. Military Satellite Communication Systems, Crosslink, Space Communications, The Aerospace Corporation, Vol. 3, No. 1 (Winter 2001/2002).
Since the 1970s, deployable antennas have been developed that can be stowed within the launch vehicle, and that can be unfurled or unfolded to a deployed configuration, providing a larger aperture for the reflector. One example is ATS-6, with a 30-ft diameter mesh reflector, discussed in J. P. Corrigan, “AT-6 Experimental Summary”, IEEE Trans Aerospace and Electronic Systems, vol. AES-11, pp. 1004-1031 (November 1975). Another deployable antenna is described in M. W. Thomson, “The Astromesh Deployable Reflector”, 1999 IEEE AP-S Symposium Digest, (June 1999) Orlando Fla., and in U.S. Pat. No. 5,680,145 “Light-weight Reflector for Concentrating Radiation” to Thomson et al. Deployable reflectors are also disclosed in U.S. Pat. No. 7,389,353” Deployable Mesh Reflector” to Bassily et al. and in U.S. Pat. No. 7,009,578 “Deployable Antenna with Foldable Resilient Members” to Nolan et al.
For multicarrier communications satellite reflectors, passive intermodulation has been a concern. Passive intermodulation issues are described generally in Boyhan, J. W., Lenzing, H. F., and Koduru, C., “Satellite Passive Inermodulation: Systems Considerations”, IEEE Trans Aerospace and Electronic Systems”, vol. 32, pp. 1058-1063, July 1996 and in Boyhan, J. W. , “Ratio of Gaussian PIM to two-carrier PIM,” IEEE Trans Aerospace and Electronic Systems, vol. 36, no. 4, pp. 1336-1342, October 2000. Contributions to passive intermodulation by particular system components are described in Henrie, J., Christianson, A., and Chappell, W. J., “Prediction of passive intermodulation from coaxial connectors in microwave networks”, IEEE Trans Microwave Theory and Techniques, Vol. 56, No. 1, January 2008, in Henrie, J. J., Christianson, A. J., Chappell, W. J., “Linear-Nonlinear Interaction and Passive Intermodulation Distortion,” IEEE Trans Microwave Theory and Techniques, vol. 58, no. 5, pp. 1230-1237, May 2010, in Vicente, C. and Hartnagel, H. L., “Passive-Intermodulation Analysis Between Rough Rectangular Waveguide Flanges,” IEEE Trans Microwave Theory and Techniques, vol. 53, no. 8, pp. 2515-2525, August 2005, Vicente, C., Hartnagel, H. L., Gimeno, B., Boria, V., and Raboso, D., “Experimental Analysis of Passive Intermodulation at Waveguide Flange Bolted Connections,” IEEE Trans Microwave Theory and Techniques, vol. 55, no. 5, pp. 1018-1028, May 2007, and Apsden, P. L. and Anderson, A. P., “Identification of passive intermodulation product generation on microwave reflecting surfaces”, IEEE Proc Microwaves, Antennas and Propagation, Vol. 139, No. 4, pp. 337-342, August 1992.
Deployable reflectors for satellite applications often use a woven wire mesh as the reflective surface. In order to reduce PIM generation, this mesh is typically stretched much tighter than would otherwise be required, while still maintaining the proper reflector shape. The tension must be maintained over a very wide range of temperatures for several years without significant breakage or other changes in shape. The fabrication and assembly of each reflector can be a very painstaking process that typically requires a large, specialized facility and many experienced people.